Building an Open Source Automated PCB Testing and Probing Fixture!

Published at : 23 Dec 2025

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Powering up a custom designed, hand soldered circuit board is risky business. One stray conductive whisker, a near invisible bridging of two adjacent pads, can cause a disaster that ends in smoke and results in time consuming troubleshooting and rework. Careful probing with a multimeter is the classic way to address this issue, but that takes time and is error prone. What this problem really demands is an automated solution, and that’s exactly what I’ve built.

Today I’m showing off my latest project: the design, construction, and coding of an automated PCB testing fixture. Connect this device to your circuit board, and it will probe the pins to ensure there are no short circuits. But that’s just the beginning - it can hook up a debug probe to your device to program microcontrollers. You can also forward analog signals to external BNC connectors, as well as forwarding any of the 16 probing pins. This allows you to assess the board with external instruments, an oscilloscope for instance, safely and easily. Finally, this board implements a universal interface that allows custom functions to check out your board. Power LEDs, read analog signals, toggle GPIO - these are just a few of the features this interface offers to make this tester truly universal. Join me as I cover this project, and stay tuned, as I’ll be releasing this project open source!

Chapters:
00:00 Introduction
2:22 Functional Overview
6:25 Circuit Description
10:44 Building the Board
13:56 Interfacing to the PCB Under Test
17:14 Code, So Much Code
20:06 Hardware Troubleshooting
22:48 GUI Demo
24:51 Future Improvements
27:24 Conclusion

Links to some of the items I’ve used in this video and/or recommend:
Resistor Decade Board: https://amzn.to/3Uc0GUU
Capacitor Decade Board: https://amzn.to/3Ubod8z
Small Capacitor Decade Board: https://amzn.to/4dRAvK3
Wiha ESD Safe Screwdriver: https://amzn.to/3A5FcSL
Official ST Link V3: https://amzn.to/4auZe5G
Quality Breadboards: https://amzn.to/45gL9HE
Jumper Wires: https://amzn.to/3VuKcbv
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I plan to use this fixture to build my LED tile backsplash, check out that project here:

Building a bigger prototype of the backsplash:
https://youtu.be/VDYZptZpK3k
Programming the PY32 for the tile backsplash project:
https://youtu.be/wtv82TfahRA
Introduction to the smart LED tile backsplash project:
https://youtu.be/3QHFTsDGk6E